Would it be possible to turn the safety valve cover round on the K's example?
I don't know, to be honest. The rebuild was 40 years ago and it may be soldered on. I appreciate it doesn't look right, especially with the other one right next to it, but what I don't tend to do is to start tinkering with older models made a long time ago, I tend to consider them my 'museum pieces'. If it appears possible without too much 'collateral damage', I may well do something about it, but not at the expense of the whole loco needing a re-spray, for example.
One example of where I did improve an older model was my Kemilway 82XXX, originally built in 1995. Some 15 - 20 years later, I realised that it didn't have any cab handrails (I had been working on a Bachmann one at the time), so that was a relatively easy job to drill small holes in the whitemetal cab and add some handrails.